What is "for one"

adv. 1 As the first in a number of examples. 2 As a single given example, often the most obvious or important one and almost certainly enough to sway the argument, of several reasons for something. 3 As one person among other people who may not hold the same opinion.

adv. as a particular one of several possibilities; "I for one feel very grateful"; "her mother for one was worried"